Many different electrical devices installed within the electrical system of premises, such as residence, office, businesses, factories, public buildings and similar require DC power to be supplied to the device.
Devices such as LED light controllers, automated switches, power outlets including environment control devices such as controls for heating, cooling, window shades, curtains as well as AC power feed to home automation appliances that are inside electrical boxes embedded into the wall cannot be fed by a separate low voltage DC power. This is because the electrical and building codes, correctly prohibits the mingling of low voltage wires with wall mounted AC power devices and power lines in conduits.
This mandates the use of AC to DC adaptors or power supplies internally built inside the small electrical outlets, switches, dimmers and the like. Such adaptors use AC transformers that are bulky and costly or power switching regulators that are costly and generate noise that must be suppressed.
Analog methods and devices to convert AC power to a low voltage and low current DC power are simple and generate very little noise, yet analog regulators waste unnecessary power and the resulting heat must be dissipated. The wasted energy by the analog regulator is far above the actual energy needed to power a given device to operate, particularly when the device itself consumes very low power of few mW, or current of few mA and a low voltage such as 5V DC for its operation. Such low power consuming devices including dimmers, current sensors and similar devices, using low power consuming CPU are disclosed in a U.S. Pat. No. 7,639,907 and U.S. patent application Ser. No. 12/236,656 filed on Sep. 24, 2008, U.S. patent application Ser. No. 12/484,321 filed on Jun. 15, 2009, U.S. patent application Ser. No. 12/614,468 filed on Nov. 9, 2009, U.S. patent application Ser. No. 12/725,808 filed on Mar. 17, 2010 and U.S. patent application Ser. No. 12/761,484 filed on Apr. 16, 2010 and are incorporated herewith by reference and are referred to hereafter as the reference patents and applications. A new small size low cost analog AC to DC adaptor or power supply with lower wasted energy and lower heat dissipation is needed.